This invention relates to dynamic, or moving coil, loudspeakers. A great variety of constructions for such loudspeakers are known. The following listed U.S. patents are illustrative, but by no means representative of this variety: U.S. Pat. Nos. 3,991,286; 4,289,937; 5,042,072; 5,062,140; 5,151,943; 5,357,586; 5,381,483; 5,390,257; 5,402,503; 5,426,707; and, 5,497,428. No representation is intended by this listing that a thorough search of all relevant prior art has been conducted, or that the listed prior art references are the most relevant prior art, or that there is no more relevant prior art.
According to the invention, a loudspeaker comprises a motor stator providing an air gap, a voice coil, a support for supporting the voice coil in the air gap, a diaphragm coupled to the voice coil for reciprocation with the voice coil, and a frame for supporting the diaphragm. The motor stator comprises a back wall and a sidewall defining a somewhat cup-shaped interior, and a center pole comprising a permanent magnet. At least one of the back wall, the sidewall and the center pole comprises a thermally relatively less conductive material. A passageway is provided through the center pole. A heat sink has a first portion for surmounting the center pole. The first portion is oriented adjacent the air gap. A second portion is coupled to the first portion in heat conducting relation and extends through the passageway to conduct heat away from the air gap through the passageway. The first and second portions comprise thermally relatively more conductive material.
According to illustrative embodiments, a passageway is provided through the back wall. The heat sink further comprises a third portion lying on a side of the back wall opposite the interior. The third portion is coupled to the second portion in heat conducting relation to conduct heat away from the second portion.
According to illustrative embodiments, the first and second portions are formed as a single piece.
According to illustrative embodiments, the second and third portions comprise complementary attachment means.
According to an illustrative embodiment, the third portion includes a first surface adjacent the back wall and a second surface opposite the first surface. The second surface is contoured, such as, for example, by the addition of fins to promote radiation of heat therefrom.
According to an illustrative embodiment, the back wall comprises a first surface facing the interior and an opposite second surface. The second surface is contoured to promote radiation of heat therefrom.